1,1,1,2,3,3,3-Heptafluoropropane (i.e., CF.sub.3 CHFCF.sub.3 or HFC-227ea) is useful as a fire extinguishant, refrigerant, blowing agent and propellant. It can be prepared by the addition of hydrogen fluoride to hexafluoropropylene. British Patent Specification No. 902,590 claims a process for the manufacture of HFC-227ea by contacting in the vapor phase an equimolar mixture of HF and hexafluoropropylene in the presence of activated carbon at temperatures between 250.degree. C. and 450.degree. C. The reaction temperatures cited in the two examples of this publication were 392 to 402.degree. C. and 300 to 306.degree. C. Various problems are reported associated with operating at such high reaction temperatures including operating safety, corrosion of the construction materials involved and in particular, production of toxic products, especially perfluoroisobutylene (PFIB). U.S. Pat. No. 5,399,795 discloses the manufacture of HFC-227ea by the reaction of HF and hexafluoropropene in the presence of a weakly basic ion exchange resin. U.S. Pat. No. 5,689,019 discloses the same reaction in the presence of an antimony catalyst. Both of these patents suggest that reaction temperatures of less than 120.degree. C. are necessary in order to suppress the formation of PFIB. PFIB removal is addressed in U.S. Pat. No. 5,705,719.
There is a need for a high yield HFC-227ea manufacturing process which does not co-produce even small quantities of PFIB.